I'm about to start promoting an e-book on one of my websites. There are about 50 pages on the website and each page has about 1000-2200 unique words. Now Im thinking about adding an extra div-tag below each article with a sales text (180 words) in which i promote the book. This means that all my 50 pages will still have their unique content but also an extra 180 words that are "sitewide duplicated".
What do you guys think about this approach? Will it hurt my rankings? I have seen websites with this amount of words (about 200 words) sitewide in the right or left column. The diffrence in this case is that it will be below each article body.